1. Field of the Invention
The present invention relates to an image forming apparatus and a computer-readable recording medium storing an image forming program. More particularly, it relates to a technology of forming a print image (actual image data) from band data generated by dividing image data of a print job into bands each having a predetermined band size.
2. Description of the Related Art
Conventionally, there has been known image forming apparatuses having a printing function, such as a printer, a copying machine, a facsimile machine, and a complex machine having functions of those, have been known in which a print job for one page is divided into a plurality of bands temporarily, and the divided bands are compressed to be intermediate codes and accumulated in a memory area, and then an image printing processing of expanding the accumulated intermediate codes into bit images is executed for each page, so that the memory area can be saved.
However, in this kind of image forming apparatus, since a print job for one page is divided into a plurality of virtual bands extending in one direction, and intermediate codes for the virtual bands are generated and accumulated, it would be necessary that a user changes a direction of a sheet cassette when a sheet direction set in a print job is not matching with a direction of a sheet stored in a sheet feeding cassette. Therefore, it has been likely that an operation becomes cumbersome.
Therefore, an image forming method for forming an image including steps of generating intermediate codes based on a print job for virtual bands each having a predetermined width, accumulating the intermediate codes, and then deploying the accumulated intermediate codes into bit images for respective virtual bands has been proposed in which the intermediate codes are generated in rectangular blocks, and the plurality of rectangular blocks are arranged in any of a lengthwise direction and a widthwise direction in an image forming area to produce a virtual band. When the lengthwise direction and the widthwise direction of the image forming area are changed, a direction of generating bit images of the intermediate codes of the rectangular blocks is inversed lengthwisely and widthwisely to produce a virtual band which extends in a direction which is lengthwisely and widthwisely inversed (the directions after the lengthwise and widthwise directions are changed). Accordingly, the image forming apparatus meets changes of size and directions of the image forming area in a flexible manner (for example, refer to Japanese Patent Unexamined Publication No. H10-67147).
Further, there has been proposed a printing control apparatus in which (1) image data which is expanded from compressed image data and other image data are expanded in a band memory, and the image data expanded in the band memory is transferred to a video transfer section when a first determining section for determining whether or not an observed band is a single compressed image determines that an observed band is not a single compressed image, and (2) compressed image data is outputted to the video transfer section without deploying the image data which is expanded from the compressed image data in the band memory when the first determining section determines that the observed band is a single compressed image (for example, refer to Japanese Patent Unexamined Publication H10-240468).
However, conventional methods relying on the image forming method of generating intermediate codes from a print job for virtual bands each having a predetermined width and accumulating the intermediate codes has a problem that generating the intermediate codes for the virtual bands from a print job is likely to cause a size of a software to be large (likely to make a processing be complexed) and lower a processing speed.